The following description relates to a divided hierarchical network system based on software-defined networks, which is capable of dividing a network into smaller networks and hierarchically operating the divided networks in order to improve scalability and flexibility of an SDN-based network.
The hardware-oriented development of a network environment makes it difficult to actively and flexibly respond to a network change, and to achieve scalability. Even there is a case where compatibility between vendors or between different models of devices from the same vendor is not ensured. Thus, software-defined network (SDN) technology to divide data plane and control plane and OpenFlow protocol have gained growing attention as alternative technologies, and currently there are many applications to usecases.
As the network environment has been complicated, more improved security, automation, and scalability are required, and the SDN-based network may be an architecture that can satisfy such demand. However, the number of switches that a controller of control plane can manage is inevitably limited. Such limitation may degrade the scalability and flexibility of the network environment.